Chorizo Shepherd’s Pie

Preheat oven to 400°F.
Place the potatoes in a large saucepan, cover with cold water by 1 inch and add 1/4 tsp salt. Bring to a boil, then reduce heat and simmer until the potatoes are fork tender, 20-25 minutes.
Heat the olive oil in a large ovenproof skillet over medium-high heat. Add the chorizo and cook, breaking up with a spoon until browned, about 5 minutes. Add the chicken and cook, breaking it up with a spoon, until cooked and slightly browned, about 5 minutes.
Add all but 1 tablespoon of the scallions to the skillet, along with the corn, tomato paste,cumin, chili powder, 1 tsp salt and a pinch of pepper. Cook, stirring until the corn is heated, about 5 more minutes, Add the tomatoes and the chicken broth, Bring to a simmer, then reduce heat to medium-low and cook, stirring occasionally, about 10 minutes or until slightly thickened.
When done, drain the potatoes and let cool slightly. Return to the pot and add the sour cream and butter and mash well. Stir in the cheese and season with salt and pepper to taste. Spoon the mashed potatoes on top of the skillet mixture, then spread with the back of the spoon.
Transfer the skillet to the oven and bake until bubbling around the edges and the topping is browned in spots, about 20-25 minutes. Let rest 10 minutes then sprinkle with the reserved scallions before serving.